The present invention relates to a washer for a fastening element, having a circumferential flange, having an annular washer body provided with an opening, and having at least one holding web. The invention further relates to a fastening element having a washer of this type.
A washer of the generic type is known from EP 1 091 135 A2. This washer has a washer body having at least two formed-on holding lugs, which can be placed around a circumferential flange provided on the fastening element. The washer is thereby held captively against the fastening element.
When a nut with washer is tightened on a fixed screw bolt, the washer is meant not to twist relative to the clamped structural part. To this effect, the coefficient of friction between the washer and a structural part is enhanced by the fact that notches are provided on the washer body of the washer. These cause the washer to remain on the surface of the structural part as tightening takes place on a screw bolt, even if the coefficient of friction between washer body and structural part is low per se.
German utility model DE 94 00 671 U1 describes a washer which, instead of holding lugs, has an annular web running round the washer body. Measures to enhance the coefficient of friction between washer body and structural part are not disclosed. In this embodiment, there is additionally the risk of nut and washer sticking together when surface coatings are applied.
U.S. Pat. No. 2,151,919 A likewise relates to a nut having a washer, the washer body of which has on the top and bottom side notches which interact both with the surface of the structural part and with the bottom side of the nut. The notches serve merely to protect against loosening of the joint.
In the use of fastening elements having washers of the generic type, there is always the risk of damage to the surface of the structural part as a result of the notches being canted or pressed in in the structural part. Moreover, the manufacture of the previously known washers, with the modifications of their washer bodies, is complex, since the notches or other surface alterations have to be added subsequent to the washer having been made.
The object of the present invention consists in providing a washer of the generic type, which, whilst offering comparable performance, is of simpler configuration and easier to make and can be used without damage to the surface of the structural part, and in which the risk of fastening element and washer sticking together is at least reduced.